Tank for a liquid-filled shell transformer or shell reactor

A tank for a liquid-filled shell transformer or shell reactor, comprising:

• a lower tank portion comprising a bottom plate and lower sidewalls, and an upper tank portion, wherein the upper tank portion comprises an inner tank portion with inner sidewalls and an outer tank portion with outer sidewalls, wherein the outer sidewalls are arranged radially outwardly with respect to the inner sidewalls such that the outer tank portion surrounds the inner tank portion,
• the lower tank portion and the inner tank portion being joined together along a substantially horizontal first perimetric joining line and defining an internal space for housing an active part of the shell transformer or shell reactor and an insulating liquid, wherein a space is formed between the inner sidewalls and the outer sidewalls, wherein the space is in fluid communication with the internal space for housing the active part of the shell transformer or shell reactor and insulating liquid, and
• the outer tank portion and the inner tank portion being joined together along a substantially horizontal second perimetric joining line, wherein the tank further comprises a tank cover configured to be joined to an upper end of the outer sidewalls of the outer tank portion.